Re-added debug instructions.

Copied from https://github.com/BUS-OGD/jester/blob/old-jester/HACKING.md (commit ee368a2)

HACKING.md

@@ -0,0 +1,22 @@
+# How to debug Jester
+
+You attach a graphical debugger ([node-inspector]) to the unittests, or to the compiled jester.js
+
+### Attaching the debugger to the compiled jester.js
+
+1. Start node-inspector on port 8080:
+
+        $ cd <jester source dir>
+        $ .\dist\node_modules\.bin\node-inspector --web-port=8080
+        info  - socket.io started
+        visit http://0.0.0.0:8080/debug?port=5858 to start debugging
+
+2. Start jester in debug mode:
+
+        $ .\dist\node.exe --debug-brk .\dist\jester.js
+        debugger listening on port 5858
+
+3. Open a browser on http://localhost:8080
+4. place your breakpoints and press the play button to start running jester.
+
+[node-inspector]: https://npmjs.org/package/node-inspector